Read only memory with optimized dimension for improved performance and chip area utilization

ABSTRACT

a read only memory on a semiconductor substrate having metal word lines and diffused bit lines with optimized dimensions for a selected performance and storage capacity with the metal lines being along an X dimension and the diffused lines being orthogonally related to the metal lines along a Y dimension. The X dimension for the substrate is given by the relation X = 2 N  · WL · K1 where 2 N  is an integer definitive of the number of words on a metal line where N is any integer power greater than zero; WL is word length which equals the number of storage devices per word selected for a word and K1 is a constant definitive of the average spacing in mils between the storage devices along the first length, and the Y dimension being given by a second relation Y = K2 · QN where K2 is a constant definitive of the spacing in mils between the adjacent rows of storage devices along the second length and Q is the number of said words. Changing the aspect ratio for an array permits the performance of a read only memory to be changed to a different set of X and Y dimensions.



